Mobile phones are not software but they have inherent anti-features which made a lot of people avoid them like fire. For example, the way mobile phones connect to the mobile network, through towers, by design, makes it a surveillance system. And the SIM card companies keep the data of where the phone goes. Notice how for this surveillance, the software on the phone is irrelevant. It could be Free or it could be Non-Free. Surveillance is done in a different way. So requiring a cell phone is a big issue.
